The Enbridge Gas (EG) Ontario network in Canada encompasses over 150,000 km of distribution pipelines and approximately 3,700 km of transmission pipelines. System-wide risk assessments indicate that external and internal corrosion, external interference, and geohazards are some of the most prevalent integrity hazards across the system.

EG Ontario completed an integrity and risk assessment on two parallel Nominal Pipe Size (NPS) 12 (Nominal Diameter, DN 300) natural gas pipelines crossing a navigable body of water that identified internal metal loss as a hazard requiring further investigation. Traditional in-line inspection (ILI) technology could not be employed to collect the necessary condition data because of unique challenges associated with the lines. For instance, each pipeline has a single access point for ILI tools, is mounted with recurrent metallic weights used for buoyancy control, and possibly contains liquids that may have accumulated over the years of service.

For these reasons, an innovative solution was required to overcome these challenges. EG Ontario collaborated with ROSEN Group (ROSEN) to develop a custom Eddy Current (EC) measurement system to be combined with an existing tethered crawler apparatus outfitted with an axial magnetic flux leakage (MFL) ILI tool. The crawler design aims to overcome the single access point challenge, while the combination of MFL and EC technologies enables the evaluation of internal corrosion, surmounting the interference posed by metallic appurtenances and the impact from potential pipeline liquids.

To verify the functionality and adequacy of this customized solution, ROSEN conducted laboratory pull-tests at their facility in Lingen, Germany, by simulating operational, geometric, and material conditions analogous to those expected in the field. This paper describes these tests and highlights how the ensuing results will support the field deployment plan in 2025 and beyond.